yes, food allergy showing in ears is common and often overlooked. My boy had dreadful ears when he was around 2, totally out of the blue. They were so bad he had to have a clean under GA. Vet (who I know well) said they were so bad they would have involved the RSPCA if they hadn't known me and known that I have been in and out to them dealing with the problem. Sorry but I don't think the antibio eardrops will help as the issue will be fungal. It might be the new biscuits but it might not. What sorted it for my boy was removing all pork duck and dairy from his diet and this includes any food, dog or human that does not list the actual ingredients on the packet.....To sort the inflammation in the ears......allergy causes inflammation, inflammation prevents ears drying so nice hot damp ear = fungal infection.....I used cortavance spray, you have to spray a little on the earflap, not into the ear, or spray a little into a tiny pot and drip it on the earlap so a tiny bit trickles into the ear. Its on prescription, talk to your vet. best and hardest thing with diet is to do an elimination diet, cook for the dog yourself, one carb and one new protein. If the inflammation subsides, then its likely a food thing give dog a month (six weeks is better) on elimination foods then gradually add back ingredients one at a time NO mixed foods or food that say things like "animal derivatives" without saying which animal. phew......shout if you want any more drivel :)